Protein Concentration Sensor Based on Exceptional Points in Whispering-gallery Microdisks

Abstract

Abstract Protein concentration detection is of great importance for biological research. Research on biosensors continuously always pursues higher sensitivity and interference immunity. If a system at exceptional point is subjected to a small perturbation, the two coupled modes will rapidly shift and split. The feature can be used for ultra-highly sensitive detection. Therefore, this paper proposes a whispering-gallery microdisk sensor at exceptional point that can be used for protein molecule concentration detection. The EP is introduced by a small hole in the solid microdisk. When microfluid containing protein flows through the small hole, the protein molecules will attach to the wall of the hole, resulting in a large complex frequency splitting. Thus, this system is extremely sensitive for protein concentration. Theoretical analysis shows that the sensitivity of the architecture is tens times higher than that of the conventional microcavity sensor.